The present invention relates generally to a machine for the processing of packing containers. More specifically, the present invention concerns a processing machine having drivable means of transport for the moving of the packing containers between different processing stations.
In the manufacture of non-returnable packages for liquid dairy goods and the like, a material web of a flexible, but relatively shape-retaining, laminated material is used which includes layers of paper, thermoplastics and possibly aluminum foil. The material web is supplied in the form of a roll to a packing machine which successively converts the material web to a tube or hose by sealing the longitudinal edges of the web to one another. This liquid-tight tube is filled with contents, whereupon it is divided into individual, substantially cushion-shaped packing containers by compression and sealing together along zones situated at equal distances, extending transversely over the material tube. The packing containers so obtained are formed in conjunction with the compression and sealing together to substantially parallelepipedic units, which are separated from each other by cuts in the transverse sealing zones. The parallelepipedic shape is disturbed, however, by the sealing zones converted to projecting sealing fins as well as by four triangular, double-walled corner lugs which for reasons of geometry are formed of excess material during the conversion from cushion-shape to substantially parallelepipedic shape.
Each individual packing container is then conveyed further to a machine, possibly built together with the main packing machine, for the processing (so-called final shaping or final folding) of the packing containers. In such a machine, among other things, the sealing fins as well as the corner lugs are folded in against and jointed to the container body proper so that a packing container of a more correct parallelepipedic shape is produced.
This processing or final folding of each individual packing container manufactured by the packing machine takes place successively as each packing container is moved between and is processed in different processing stations in the final folder. The time for the whole processing cycle is determined, among other things, by the heat-sealing times of the thermoplastic material, which renders it difficult to design a final folder which operates at sufficiently high speed to serve fast packing machines.
The movement of the more or less finished packing containers step-by-step also makes high demands on accuracy, if it is to be ensured that each packing container is moved to the exactly correct processing position at each station.
Previously used final folders cannot process the packing containers with sufficient accuracy and safety at the high speeds of operation which are required in modern packing machines, and it is therefore in general desirable that a faster and more accurately working final folder should be designed.
It is an object of the present invention therefore to provide a machine for the processing of packing containers, this machine not being subject to the disadvantages of earlier designs, but working safely and rapidly.
It is a further object of the present invention to provide a machine of the abovementioned type which safely moves and guides the packing containers between accurately fixed positions in each processing station.
It is a still further object of the present invention to provide a machine which is capable of performing a safe and accurate folding and forming of sealing fins as well as corner lugs.
It is a yet further object of the present invention finally to provide a final folder which in spite of making it possible to extend the processing time in each individual processing station has a high overall capacity.
These and other objects have been achieved in accordance with the invention by a machine of the type mentioned earlier in which the means of transport includes intermittently rotating support means or a drum which along its periphery is provided with holding means or devices for individual packing containers. The holding devices are arranged at a mutually uniform pitch which corresponds to the pitch between the processing stations fixed around the means of transport, and are adapted so that during rotation of the means of transport they are maneuvered between an open and a closed position.
Preferred embodiments of the machine in accordance with the invention have been given the characteristics which are evident from the description below.
Through this design of the machine in accordance with the invention, a machine for the processing or final folding of packing containers is provided which not only brings about a very high working speed, but also makes it possible to increase the available processing time at each station. At the same time, the machine guarantees a safe removal of the partially processed packing containers between accurately fixed positions at each processing station. The machine in accordance with the invention also provides a safe guidance of the packing containers during the transport between the processing stations and ensures finally that the folding-in of the corner lugs is taking place step-by-step in a well-defined and accurate manner.